 # Value Of c

The speed of light is defined as the speed with which a light photon travels in the vacuum. It is denoted by the alphabet c and measured using SI unit m/s. The value of velocity of light or value of c is a constant at any part of the universe. This physical constant has multiple applications at various disciplines of physics.

## Speed of Light

The velocity of the light in the vacuum or air:

The speed of light c = 299792458 m/s ≅ 3 × 108 m/s.

The velocity of light can be expressed in terms of mph or km/s. That is-

• The speed of light in mph 186,000 miles per hour.
• The speed of light in air is 299792 km/s.

Hope you have learned the value of c or the value of the speed of light in vacuum along with units of velocity.

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## Frequently Asked Questions – FAQs

Q1

### Define speed of light.

Speed of light is defined as the speed with which a light photon travels in a vacuum.
Q2

### How is speed of light measured?

The speed of light is measured by using SI unit m/s.

Q3

### Is value of velocity of light constant?

Yes, the value of velocity of light is constant.
Q4

### What is the velocity of the light in the vacuum?

Velocity of the light in the vacuum is = 299792458 m/s ≅ 3 × 108 m/s
Q5

### What is the speed of light in air?

The speed of light in air is 299792 km/s.
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